Some data storage systems may implement a replication functionality. Replication comprises continually duplicating in real time one storage volume to another storage volume. Replication may differ from merely copying or backing-up one storage volume to another volume in that replication implies an on-going link between the volumes, such that, as changes and new writes are made to the one volume, the other volume is also updated with the same.
For example, in one replication arrangement, a first volume of a first storage array is replicated to a second volume of a second storage array. In this example, the first volume may be read from and written to by hosts via the first array, while the second volume may be read from by hosts via the second array but may not be written to by hosts. When a write request is received by the first array, the first array writes the data to the first volume while also sending a copy of the data over a replication channel to the second array for storing in the second volume.
Replication is often used to mitigate the risk of data loss. For example, if one of the volumes in a replication relationship were to fail, then the data stored therein would not be permanently lost because it would be available on the other volume of the replication relationship.